absolute and relative bioavailibility and their use in clinical practice. Therapeutic drug monitering. Flashcards
Definition of pharmacokinetics (Ph.K):
mathematical basis to assess the time course of drugs and their effects in the body
⦁ Absorption
⦁ Distribution
⦁ Metabolism
⦁ Excretion
Definition of Bioavailability (F):
fraction of unchanged drug reaching the systemic circulation that can acomplish effect.
Bioavailability (F): in iv
F is assumed to be equal to a unit (100%).
Bioavailability (F) oral prep
less than 100% for two 1) ¾ incomplete extent of absorption
2) first-pass elimination
ioavailability (F)
Clin.importance
gives info about : 1.) absorbtion; 2.) first pass effect
bioavailability indicies
-pharmacokinetic indicies
AUC-area under blood conc time curve measure of extent of drug bioavailability
-biopharmaceutical indicies AUC CMAX- peak serum conc TMAX-time taken to reach CMAX
Types of bioavailability
⦁ Absolut F:
compare F between i.v. and other routes of application
⦁ Relative F:
compare F of a new drug form with F of same drug approved by practice but in a different ROA
Therapeutic drug monitering (TDM)
involves measuring the drug plasma level at set intervals to observe 1)drug efficacy
2) ADR
3) compliance
2 types of criteria for TDM:
- Drug criteria
2. Patients’s criteria
which drugs require TDM
⦁ Drugs with a narrow therapeutic index
⦁ Patients with symptoms of toxicity
⦁ Drugs with active metabolites
⦁ In cases with complexed combination therapies with expected drug interactions
population rrequiring TDM
⦁ infants ⦁ pregnant women ⦁ the elderly ⦁ patients with GI problems ⦁ patients with liver and/or kidney disease ⦁ patients with cardiac faliure
TDM for pharmacodynamics
⦁ measurment of blood glucose of a diabetic after the intake of insulin
⦁ measurment of blood presure before and after the administration of anti-hypertensive drugs⦁ measurment of blood presure before and after the administration of anti-hypertensive drugs
